The Giant's Causeway is a mass of over 40,000 basalt columns on the NW coast of Ireland, between Portrush & Ballycastle; formed by a rapid cooling of lava hitting the sea. Folklore ascribes the formation to a mythical race of giants who laid down the rock on the sea floor as a roadway between the Scottish Hebridean islands and Ireland.

"This object of great interest forms no part of the Causeway, but is placed apart in the mountain, and consists of a number of large pillars, declining on either side to shorter and shorter ones, like the strings of a harp; and we might really imagine a giant organist sitting playing at it, especially as the basaltic pillars, when struck, give forth a metallic ring. The colonnade of pillars which constitute the pipes of the organ, have evidently been exposed by some landslip."

Descriptive letterpress from the book 'Photographs of the Giant's Causeway.'